Distributing valve arrangement for chipping hammer



April 16, 1957 H. R. FISCHER 2,788,768

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, April 16, 1957 DISTRIBUTING VALVE ARRANGEMENT FOR CHIPPING HAMMEROriginal Filed March 17. 1949 United States Patent DISTRIBUTING VALVEARRANGEMENT FOR CHIPPING HAMMER Howard R. Fischer, Utica, N. Y.,assignor to Chicago Pneumatic Tool Company, New York, N. Y., acorporation of New Jersey 2 Claims. '(Cl. 121-29) This application is adivision of parent application Serial No. 367,215, filed July 10, 1953,now Patent 2,716,393, August 30, 1955, which in turn is a division oforiginal application Serial No. 81,935, filed March 17, 1949, now PatentNo.2,672,l29, March 16, 1954.

It is an object of the invention to provide a chipping hammer which maybe easily regulated to deliver either light, delicate taps, or heavy,hammer-like blows and whereby to render the hammer adapted for use formany different purposes.

It is another object of the invention to provide an automaticdistributing valve arrangement for delivering air under presurealternately to opposite sides of the hammering piston comprisingseparable valve case sections and a valve element having two thinflanges spaced apart and an integral stem guided by the valve casesections and wherein the flanges need not have air tight connection withthe walls of the case sections, but between their peripheries and thewalls provide the passages through which the air is diverted to theopposite sides of the valve to eflTect the movement of the valve fromone position to the other and to pass the air to the opposite sides ofthe hammering piston, whereby to provide a valve arrangement forchipping hammers which will have little wear and long life.,

It is another object of the invention to provide a chipping hammercomprising a cylinder sleeve, hammering piston and distributing valveparts which can be loosely assembled in order in the outer casing andwhich will be held in place by the single connection of a throttle andblower valve containing cylinder head to the outer casing.

Other objects of the invention are to provide a chipping hamer havingdistributing valve arrangement which is of simple construction, has aminimum number of parts, easy to assembly, inexpensive to manufacture,easy to operate, compact, and efiicient in operation.

For other objects and for a better understanding of the invention,reference may be had to the following detailed description taken inconnection with the accompanying drawings, in which Fig. 1 is aperspective view of the chipping hammer embodying the features of thepresent invention being used on a wall to chip the mortar from betweenbricks thereof and with the operating lever depressed for chiselingaction.

Fig. 2 is a perspective view of the chipping hammer being used on thewall and with the operating lever elevated with the thumb to project thehigh velocity jet of air upon the work surface to clean the same.

Fig. 2a is a perspective view of the chipping hammer being used toremove weld flux.

Fig. 3 is a fragmentary side elevational view of the chipping hammerwith a portion thereof broken away and shown in section through theregion of the air jet 2,788,768 Patented Apr. 16, 1957 See blower valveand with the operating lever elevated to depress the same forbloweraotion; g Fig. 4 is a longitudinal sectional view of the chippinghammer with the hammering piston projected toward the nose end of thehammer and as viewed on line 4,4 of

I V i I 1 's 5 17 this Fig. 5 is a longitudinal sectional view taken online 55ofFig.4.- f I Fig. 6 is a perspective w'ew of the cylinder sleevere movedfrom the main casing. Fig. 7 is alongitudinal sectional view ofthewchipping hammer with the operating, lever depressed for. hammeringaction and as viewed. onl-ine 7. 7 of Fig. '1. 7 Figs. 8 and 9are/respectively enlargedtransverse sectional views taken on lines and 9-9 of Fig.7.

Fig.v 10 is :a ficollective view of the distributing valve casingsections which are in section-and of the valve element which is shown inside elevation.- T Fig. 11 is an enlarged fragmentary and sectional viewof the hammer taken through the distributingvalve' arrangement with thehammering piston its rearwand position within the cylinder sleeve andthe valve element of the valve arrangement being positioned to extendair to theforward part of -the cylinder chamber.

Fig. 12 is a fragmentary sectional View similar to Fig. 11, but withthe'hammering piston extended forwardly in the cylinder to engage withthe end of the chisel and with the valve element positioned toextendlair to the rear part of the cylinder sleeve. 1 A v 9 Referringnow to the figures, the chippinghammerof the present invention comprisesgenerally an outer. casing 21 having an-integral nose end portion22adapted to receive a chisel 23 within its opening 24. This chisel 23is held within the opening 24 by a quick'release key plug 25. The outercasing 21 is internally threaded at 26 to receive a threaded portion 27of a cylinder head 28 having a throttle valve element 29 adapted tolbedepressed by a manually-operable lever 31 pivotally connected to thecylinder head 28 at, 32. This same lever 31 when pivoted away from thethrottle valve element 29 is used to depress a blower valve element 33tocauseair to be directed through the cylinder head-randcasing and holes34 in the nose end portion 22 of the outer casing21 to direct air uponthe work surface. ,This air passes, to the work surface'with great forceand removes such par ticles and chips from the surface which have notbeen removed by the exhaust air blast'and in the manner'as illustratedin Fig. 2. f a t Fitted within the outer casing 21 is a cylinder'sle'eve35 having a hammer piston 36 slidable therein; This harnrner piston 36has a projection 37 adapted to tap the end of the chisel 23 which hasbeen extended into the 'nose end portion 22 of the outer casing 21.Fixed within the outer casing 21 by the cylinder head 28 is adistributing valve arrangement 38 with a double flange valve element 39and adapted to cause the passage of air to first one end of the cylindersleeve 35 and then to the oppositefend thereof whereby to cause thereciprocation of the sham nier piston 36 at a speed dependent upon theextent of downward movement of the lever 31 and of the throttle valveelement 29. The hammer piston 36 can accordingly be made to delivereither fast blows upon the chisel 23 or slow taps. J The cylinder head28 is locked in the outer casing 21, against turning movement by alocking ring 41 seated in aligned recesses 42 and 43 0f the respectivecasing and head parts, and having a radially-inwardly bent'end 44 withinaligned peripheral slots 45 and 46 of the respective casing and headparts. An air hose 48 is connected to a threadedopening 49' inthecylinder head 28. Extending from this threaded opening; 49 is a yalvecham: ber 51 into which valve elements 29 and 33 are extended 7 3 toopen pom 52 and 53 respectively. A' plug 54 is disposedinavthreadedopening at'the bottom of the' cylinder 7 head whereby, if desired, anattachment of the hose 48 can be made to the bottom of the cylinderhead. 7 The plug-54 can be then'inserted in the threaded opening 49.

Air passes from the valve chamber 51' through port 52 w en lever 31 isdepressed and" the valve element 29 lowered into" the chamber 51 so:that its closing portion 55 dropssuflicien-tly to allow air to pass to agroove 56 on the valve element 29 and to distributing valve'chamber 57inthe cylinder head. The valve element 29 is a an exhaust hole 93 whichis uncovered by the piston as urged toward its elevated and closedposition by a spring 1 58 and plu'g '9i- I V lThedistributing,valvearrangement 38 comprises two opposing s eatipartsor casing sections 61 and 62 separable from one another upon thedistributing valve arrangement being'jrnadeffr'eeof the casing but heldclosed upmreneianqther, by the cylinderhead 28 on being connectedwith-the outer casing 21','Figs .4, 1'1 and 12. Cir cumfereritiallvspaced within'the casing section 61 are a plurality oflongitudinally-extending holes 63 through which the live aiif'is' passedfrom the valve chamber 57 to'an annular manifold recess 64 cut in theface of the casing section .61; Frornthe manifold recess, the live 'airpa'sses 'radially inwardly'through a thin annular slot 7 65 providedbetween the casing sections 61 and 62and into space 66provide'd betweenflanges 67 and 68 of valve element"39". This space 66' provides aminiature r'es er'voinfor the air and permits the valve element 39 toshift from one position to'the other. On the valve casihg section is aradially flat seat 69 agains t which a'complernent ary fiat face of thevalve element is forced when moved into. casing section 61. On thecasing section" 62 isa radially. flat valve seat 70 against which onopposite complementary flat face of the valve element .39 is forced whenthe valve element is moved toward that section. The valveelemen't-39hasa stem 71 which entersa" hole 72 to be'supported' and guided in itsaxial movement within the distributing valvecasing sections. .The twoflanges 67 and 68 of the valve element 39 are slightly smaller indiameter than the bores 67 and 68' (Fig. 12) of the valve casingsections which allowthe correct volume of air to flow past the flangesto the front and rear ofithe cylinder sleeve 35 to operate the hammeringpiston 361 If the valve element 39 has been moved tp the right, asviewed in Figs. 5, 7 and 11, air

it moves'rearwardly in the chamber 83. The pressure in the front" end ofthe chamber 83 thereupon instantly drops. The hammer piston 36 continuesto move rearwardly under its momentum and compresses theairinthe rearend of the chamber 83 into an axial counterboreor pocket 39 (Fig..11) ofthe valve element, which pressure, together with the pressureof'airflowing over the flange 67 through seat opening 69' acts to shift thevalve element 39 rearwar'dly to engageseat 69 The pressure willthereupon drop in the passages leading from" the distributing valve 38.The variable force of the blow results from the light sensitive pulleyvalve'element 39,

' the throttle valve 55 and thecontrol' lever 31.

The air from the small chamber 66 between'the flanges 67 and 68 of thevalve element 39 then; passes over the flange 68, through seat 70' andport 94in the casings'ecw tion 62, to enter the rear of the chamber 83to urge the piston forwardly for its next hammering action. As soon asthe exhaust port 84 is uncovered on the forward stroke, exhaust port 93is closed over by the piston, the driving pressure on the pistondiminishes and pressure is builtup at the opposite seated end 69 of thevalve member, which pressure, together with the pressure air flowing:over the flange member 68 into the passage 94 moves the valve elementforwardly to engage seat 70 and to open the passages to the forward endof the chamber 83 and effect the return of the piston. n

, While only one relief 86 and one groove 81 has been described, it isto be understood that thecylinder sleeve also has a' diametricallyopposite relief 86 and'a di:

passes flange 67, seat 69, longitudinally-extending charnber 75 in thevalvesection 61, radially-extending passage 76, aligned peripheral slots78 and 79 in the respectivevalve casing'sections 61 and 62,longitudinally-extending slot 81' in the cylinder sleeve 35, holes 82 inthe cylindersleeveto the front of the cylinder sleeve chamber 83 andahead ofthe piston 36 whereby to return the piston 36 to the rear of thecylinder sleeve chamber. While this is taking place, the air in the rearof thechamber 83 is exhausted through largehole 84 to alongitudinally-em tending passage 85, Fig. 5,v provided by relief 86 cutfront the exterior of the cylinder sleeve 35. This relief begins at'apo'in'ton thecylinder sleeve removed from the rear thereof andterminates at the forward end of the cylinder sleev e -to allow'the airto pass forwardly thereof to air lioles'34 aiid exhausted upon theworking surface.

bya flaring '88. The nose end of the cylinder 35 is peripherallyrelievedzat 89 toprovide an annular passage 7 through which the airleaving-longitudinal passage 85 passes to air-holes 34. The'cylindersleeve'35 has a.

ame'trically opposite groove 81. The valve casing sec-i tions 61 and 62likewise have corresponding passages and slots for the delivery of airto the diametrically opposite groove 81. Likewise, the relief 86 at theopposite side of the sleeve has exhaust openings 84, 92 and 93 andterminates at the annular relief '89 on the nose end of the cylindersleeve.

' Upon release of the operating lever 31, the throttle valve 29 isreturned to its closed position and the lever 31 is raised to itsneutral position, as viewed in Fig. 4. By lifting the lever rearwardly,the blower valve 33 is depressed and air Will be admitted from thechamber 51 to the blowing air port 53. This blower valve 33 is normallyurged toward'a closed position by a spring 95 and a plug 96 threadedinto the cylinder head. 28. There are two ports 53, Fig. 5, connectingrespectively with longitudinally-extending passages 97 in the cylinderhead 28' which flare outwardly to provideoutlet ports 98' on the forwardend of the cylinder head.

The cylinder head 28 is provided with an annular rc-' cess 99 whereby toprovide an annular chamberlOl be tween the cylinder head and the casing21. This annularchamber 101 has" communication with slots 78 and 79,Fig. 11, in the respective valve casing sections 61' and 62 and to thegrooves 81 on the exterior of the eviinder sleeve35. From these grooves,the air enters the front of the chamber 83, causing the hammeringpiston36' to be moved rearwardly and touncover the" sleeve opening 93 topermit the air to pass through passages 85, annular space 91' and holes34. This air moves in a steady stream and will be projected with greatforce-upon tion'to a position to depress the blower valve 33, blower;action will be effected and a removal of thecu-ttings'or chips on thesurface being worked willaresult,-

Referring now particularly to Figs. 4 and 7, there is shown the chiselretaining arrangement. The chisel 23 has a portion thereof adapted tofit the opening 24. Intermediate the length of this portion is a slotadapted to receive the retaining plug 25. This retaining plug is roundand has a tapered projection adapted to enter the chisel slot and ashoulder adapted to engage with a shoulder of plug opening 108 in thenose end 22 of the casing 21. The retaining plug 25 is held in place bya split spring ring 109 adapted to fill an annular recess on theexterior of the nose portion 22. The ends of the ring terminate againsta handle portion of the retainer element. The slot in the chisel elementis sufiiciently long to permit the axial displacement of the chiselresulting from the hammering action.

The sleeve 35 with the piston 36, the distributing valve sections 61 and62 with the valve element 39 disposed between them, are easily assembledwithin the outer casing 21 in the order mentioned and by the mereconnection of the cylinder head 28 containing the valves 29 and 33 andthe manually-operable lever 31 for operating these valve elements aresecured firmly within the casing 21 against axial displacement. The ring41 is finally snapped into place on the outer casing and the cylinderhead to prevent the outward turning of the cylinder head from the outercasing 21.

The chipping hammer is of light weight, easily handled and has manyuses. Some of such uses are channeling brick before repainting, cuttingwindings in electric motors, scraping barnacles from ship bottoms,cleaning putty from steel window sashes, chiseling wood in patternshops, making grafting incisions in trees, removing heat treat scale,redressing millstones and numerous other uses.

While various changes may be made in the detail construction, it shallbe understood that such changes shall be within the spirit and scope ofthe present invention as defined by the appended claims.

What is claimed is:

1. In a pneumatic hammer adapted to deliver rapid blows and having apiston cylinder with a hammer piston slidably arranged therein; adistributing valve arrangement comprising opposed separate casingsections, arranged to form between them a cylindrical valve chamherhaving an annular surrounding Wall and end walls at right angles to thelatter; one of the casing sections having a ring of longitudinallyextending holes for admittance of pressure air to an annular manifoldcavity formed in said casing section; the casing sections providingbetween them a thin annular slot communicating the manifold cavitydirectly and radially with the center of the chamber, and the crosssectional area of the manifold cavity being relatively greater than thatof the longitudinal holes and the thin slot, whereby a multiplied anduniform thin stream of air pressure is admitted radially through theentirety of the thin slot into the valve chamber; one of the end wallsof the valve chamber having an axial passage communicating directly withthe driving end of the piston chamber, and the opposite end wall havingan outer axial extension into which extends from the valve chamber asecond axial passage communicating radially with passages leading to thereturn end of the piston chamber, a boss about each axial passageprojecting slightly into the valve chamber and having a broad radialflat end face forming a valve seat; an elongated valve rod projectingaxially from the valve chamber freely into that axial passage whichextends into the said end wall extension, and having its end portionsupported for slight axial movement in a complementary bore of thelatter wall extension; a sheave form valve member disposed in thechamber, axially carried at the opposite end of the valve rod, andincluding a pair of radial annular flange members spaced by a V groove,and a valve head formed by a boss projecting axially from the outer faceof each flange; each valve head having a radially extending broad flatend face adapted for sealing engagement with one of the valve seats; thevalve member being axially reciprocable to unseat one valve head fromone exit passage and to seat the other over the opposite exit passageupon each directional movement of the valve; the valve member beingarranged to reciprocate over a short distance so that the thin annularslot is at all times in communication with the V groove between theflanges, and the peripheries of the flange members being in close spacedrelation to the cylindrical wall of the valve chamber whereby the thinstream of pressure air forcefully entering the valve chamber to the Vgroove flows forcefully and uniformly over the peripheries of the flangemembers to the opposite sides thereof so as to influence the valvemember to move from one seated position to the other; and the pistoncylinder including exhaust port means controlled by the movements of thepiston hammer for relaxing counter air pressure in the piston cylinderover the unseated end of the valve member and increasing it over theseated end after the piston hammer has reached a predetermined positionin moving in either direction, whereby the valve member is readilyreciprocable from one position to the other under the influence of thepressure air in the valve chamber and the compressive action of thepiston hammer in the cylinder.

2. In a pneumatic hammer as defined in claim 1, wherein that valve headarranged to seat over the exit passage leading directly into the drivingend of the piston cylinder is characterized by an outer counterboreequal in diameter to the said passage and of relatively smaller diameterthan the piston cylinder, whereby the compression created by the pistonhammer on this valve head when the latter is seated in multiplied on areturn movement of the piston to cause a swift unseating thereof as wellas to enable a full return of the piston and to provide a volume ofcompressive air effective in supplementing the incoming pressure air inre'driving the piston.

References Cited in the file of this patent UNITED STATES PATENTS761,414 Secher et al. May 31, 1904 1,264,856 Power Apr. 30, 19181,789,698 Curtis Jan. 20, 1931 2,177,158 Smith, Jr Oct. 24, 1939

